Liquid sample handling system and method

ABSTRACT

A system and method for automatically handling fluid sample transported in open containers along a predetermined path employs the steps of submerging the end of a suction probe beneath the surface of sample in one of the containers while connecting the other end of the probe to form a path in fluid communication to an analysis chamber where the liquid sample is to be examined. A bubble of vacuum is introduced into the analysis chamber to withdraw a related portion of sample from the container into the analysis chamber. The portion of sample remains in the analysis chamber for a period sufficient to obtain analysis thereof, and, subsequently, by applying suction to the analysis chamber and probe, the sample portion and remaining sample in the open-topped container are withdrawn for discharge. Subsequently, the path of sample is purged by drawing large volumes of air through the path for a period sufficient to remove any residue of the sample therefrom. In addition, preliminary steps of submerging the end of a hollow probe into the sample are taken whereby by pumping air through the hollow probe, bubbles are injected into the sample to stir it prior to its use in the analysis chamber. As the hollow stirring probe is withdrawn, means are provided for wiping the exterior thereof with absorbent material to remove residue of sample clinging to the stirring probe.

United States Patent 3,478,598 11/1969 Nielson................. 3,252,327 5/1966 Ferrari.........................

Primary Examiner-S. Clement Swisher Attorney-Flehr, Hohbach, Test, Albritton & Herbert PATENTED JAH 4 i972 SHEET l F 2 INVENTOR wAlTE M. sHELToN Y p/ W 4 f W ATTORNEYS PATENTEU JAN 41972 SHEET 2 UF 2 ATTORNEYS LIQUID SAMPLE HANDLING SYSTEM AND METHOD BACKGROUND OF THE INVENTION This invention pertains to a system and method for automatically withdrawing a liquid sample from a test tube and transferring a portion of the sample to means for optically examining same.

I-Ieretofore, systems have been provided wherein a succession of test tubes or other small containers have been cyclically moved along a predetermined path while carrying liquid samples, such as blood serum and other liquid materials. At a predetermined location along the path, sample is extracted and transferred to means for examining it. The present invention constitutes an improvement for handling the liquid sample at that stage where it is to be withdrawn for examination.

SUMMARY OF THE INVENTION AND OBJECTS In general, there is provided a system and method for automatically withdrawing liquid sample for examination from each of a series of advancing containers. The system includes a hollow probe for entering liquid sample in each container. Means are also provided to be movable between retracted and advanced positions for holding the probe disposed at a position for entry into each of the containers. Fluid lines couple the probe to an analysis chamber for receiving sample from each of the containers for examination in the analysis chamber. Means are provided for subjecting the analysis chamber to a momentary drop in pressure forming a partial vacuum therein for subjecting the analysis chamber and submerged probe to the partial vacuum for drawing a related predetermined portion of the liquid sample into the analysis chamber.

In the above general way, the system disclosed herein introduces a bubble of vacuum into the analysis chamber (as distinguished from the use of a continuous suction) so as to control the amount and condition of the sample drawn into the analysis chamber.

Subsequently, the balance of the liquid sample is withdrawn from the test tube and discharged to a waste container and then the fluid lines are purged to remove substantially all traces of the liquid sample whereby the next successive liquid sample can be examined without contamination by residue of the earlier sample in the fluid lines.

In general, it is an object of the present invention to provide an improved system and method for handling liquid sample.

It is another object of the present invention to provide a system and method for handling liquid sample in a manner free of contamination of a subsequent sample by residue from a preceding sample.

A further object of the present invention is to provide a system and method of handling liquid sample in a manner whereby the fluid lines are purged between each successive sampling procedure.

The foregoing and other objects will become more readily evident from the following detailed description of a preferred embodiment when considered in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a schematic view in perspective of a system according to the invention shown with certain parts in section for clarity;

FIG. 2 shows a timing chart for the operation of one complete cycle of operation of the system shown in FIG. l;

FIG. 3 is a schematic perspective view in enlarged detail showing a portion of the apparatus employed in the system in FIG. 1 for providing stirring of the contents of test tubes prior to analysis; and

FIG. 4 is an enlarged perspective view, viewed from below, showing a portion of the stirring assembly of FIG. 3.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIG. 1, a cyclic carrier 9 is schematically shown as provided in conventional style for carrying a number of test tubes l1 or other suitable open-topped containers, each of which is intended to contain liquid sample therein. The cyclic carrier operates in a direction as shown by the arrow 13 in incremental steps so as to successively arrest one of the test tubes 1l disposed directly beneath a hollow extraction probe 14 in the foml of a small diameter tube of stainless steel carn'ed in the outer end of a transverse support ami 16. The height of probe 14 is vertically adjustable by means of a set screw 17 as shown.

Support arm 16 is arranged to be driven between retracted and advanced positions by means of the plunger 18 connected by air line 19 to a pneumatic control valve 21 whereby, for example, in the position shown, line I9 is connected to a vacuum line 22 (connected to a suitable pump) for holding plunger 18 in its upper position.

Shifting of the spool 23 of valve 2l downwardly (against the action of spring 24) serves to disconnect vacuum line 22 and to couple a pressure line 26 to air line 19 for driving plunger 18 downwardly to its extended position. This serves, of course, to carry the extraction probe 14 downwardly into a test tube 11 where the lower tip of probe 14 will be submerged well beneath the level of sample carried in the test tube.

Spool 23 is transferred from one condition to the other by means of a cam 27 carried on a cam shaft 28 continuously rotated by a drive motor 29. The cam 27 is schematically shown simply as an elipse in FIG. l, but it is to be understood that cam 27 (and the other cams 3l, 32, 53) are formed with the usual operating lobes (not shown) which serve to cause them to carry out the functions shown in FIG. 2 in the timed relationship thereshown. Thus, cam 27 is arranged whereby during a portion of its rotation, it will drive the spool 23 downwardly against the spring 24.

Cams 3l, 32 are also carn'ed on cam shaft 28 for rotation, and these two cams serve, respectively, to close the contact points of microswitches 33, 34 during a portion of the cyclic rotation of the shaft 28 as noted in FIG. 2.

Referring to FIG. 2, assuming the start of a cycle of operation at time A as graphically shown, it is readily evident from inspection of trace 57 that motor 29 will be energized at that time, as from the power supply 37. This, of course, will cause a rotation of cam 27. By properly synchronizing the stepping action of cyclic carrier 9 advancing the test tubes l1 in discrete increments along the direction of arrow 13 in conventional style, it is possible to form cam 27 in a manner whereby, upon arrival of each successive test tube directly beneath the hollow extraction probe 14, cam 27 will serve to drive spool 23 downwardly so as to couple the pressure line 26 to line 19 thereby driving plunger 18 downwardly and carrying probe I4 with it.

Set screw 17 makes it possible to insure that the lower tip of probe 14 will be properly submerged in sample in test tube ll.

The foregoing insertion of probe 14 occurs substantially at time 8, as shown in FIG. 2.

Means are provided whereby at substantially time C" (FIG. 2), a bubble of vacuum" is introduced into the extraction line 1S so as to extract a predetermined quantity of sample from the test tube 1l and transfer same into a flow-through style analysis chamber l2 of any suitable type, such as employing a conventional spectrophotometer device diagrammatically indicated by the reference 20 or other suitable means for analysis of the sample.

Thus, it is to be understood that the object at this point is merely to introduce an appropriate volume of sample into analysis chamber 12 whereby it can be examined and subsequently discharged. By means described below, the proper amount can be assured by employing a related bubble of vacuum.

Accordingly, fluid may enter the top of analysis chamber 12 and be drained from the bottom thereof along a fluid line 25 which branches to pass through a low-capacity valve 43 operated by a solenoid 42. The other branch of line 25 passes directly through a relatively large capacity valve 56 operated by a solenoid 54. Both branches of the discharge line 25 meet downstream of valves 43, 56 to drain via line 46 into a lowpressure accumulator placed under vacuum conditions by means of a vacuum pump 48 connected by line 49 to the interior of accumulator 47.

A waste trap 36 is also subjected to the same vacuum condition as exists within the interior of accumulator 47 whereby the discharge from analysis chamber 12 which is accumulated can be discharged into waste trap 36 by gravity.

ln order to introduce a bubble of vacuum" into the analysis chamber 12 and thereby load the chamber with a related volume of sample, a variable restriction 44 is placed in the line 46 at a location serving to couple the accumulator 47 (under vacuum) to chamber 12 via valve 43 whereby upon momentary operation of valve 43, a short transmission of lower pressure is made along line 46 via restriction 44, valve 43, line 25 and thence to the interior of chamber 12. Obviously, this momentary reduction in the pressure within chamber 12 is further transmitted via the extraction line l5 to probe 14. lf probe 14 is submerged in sample at the time, sample will be withdrawn into chamber l2 to an extent related to the degree of exposure of chamber 12 to the vacuum bubble Thus, briefly, referring to FIG. 2, it will be readily evident that at time B trace 59 indicates that probe 14 is inserted into a test tube ll by connecting the actuator 18 to pressure line 26. Subsequently, at time C from trace 62 the analysis chamber will be loaded. This is effected by the proper lobe on cam 3l closing microswitch 33 to complete a circuit traced from the positive terminal of power supply 37 along lines 38 and 39 through switch 33 and solenoid 42 to ground. Motor 29 continues to rotate cam shaft 28 and subsequently the cam lobe on cam 31 permits microswitch 33 to reopen, after a relatively short period of closure of the switch points 33. The variable restriction 44 is adjusted whereby as valve 43 is opened for this very short time, a short pulse of vacuum can be readily transmitted to chamber 12 for analysis, as for example, by mean of the spectrophotometer 20.

ln order to carry out a sufficient number of proper examinations on a single portion of sample in chamber l2, a suitable predetermined dwell period of variable nature is provided.

Thus, when probe 14 has been inserted into a test tube, microswitch Si will be closed by contact with the downward moving arm 16 and, at a suitable time during this period, a lobe on cam 53 will close microswitch 52 thereby energizing a circuit through an adjustable conventional timer 50 traced from the positive terminal of power supply 37 and thence along line 40 to microswitch 5l and back via line 55 to timer Sl). Timer 50, is, in tum, connected through microswitch 52 to coil 60 leading to ground at the negative terminal of power supply 37. This activation of coil 60 serves to electromagnetically operate a switch 65 in the motor circuit. Timer 50 can be of any suitable type of conventional construction such, for example, as may employ a bimetallic conducting element which, upon passage of current therethrough, serves to become heated so as to be moved to deactivate the time in a manner opening the circuit traced immediately above thereby deenergizing coil 60 and again closing motor circuit switch 65.

Thus, during the dwell period, sample is examined in chamber 12 to the extent desired, the period of dwell being readily adjustable by merely adjusting the conventional mechanisms of timer 50.

Subsequently, after the period of dwell has been terminated (time "F" in FIG. 2), sample remaining in chamber 12 and test tube 11 is drawn into waste accumulator 47. Thus, motor 29 is again energized, and microswitch 34 closed by its associated cam 32 to as to complete an electrical circuit serving to operate solenoid 54 which opens valve 56. Any residual fluid remaining in cell l2 is then removed via valve 56 under the vacuum of accumulator waste trap 47 under suction of vacuum pump 4d. Upon closure of solenoids 42, 54, waste will then transfer to the waste jar 36 by gravity, since the vacuum level in the waste jar 36 is substantially kept at the same level as that in accumulator 47 Further, referring to FlG. 2, it will be readily evident that by inspection of trace 6l, the operation of valve 56 will initiate a drain-out of chamber l2 at time G" which continues to a time H." lnasmuch as the probe is still inserted (not trace S9), any remaining sample in test tube l1 will also be drained at the same time due to the large capacity of valve S6.

Following drain-out of chamber l2 and test tube ll, solenoid 42 again serves to open valve 43 while solenoid 54 is operated to close valve 56. ln this manner, the fluid lines designated 25a, 25h and 46 will be cleared of any residual fluid remaining therein which, conceivably, could otherwise block or vary the transmission of the next bubble of vacuum."

This clean-out period for the intermediate conduits 25a, 25b, 46 is shown in FlG. 2 in the region designated 70 for trace 62.

Means are provided for purging the lines with a large draft of air. Thus, at this point, cam 27 serves to shift spool 23 so as to apply vacuum to plunger 18 thereby withdrawing probe 14 to a level well clear of its associated test tube. Solenoid 54 is then energized to open its associated valve 56 while solenoid 42 remains energized to keep its associated valve 43 open. ln this manner (both valves being open), a large volume of air will be drawn through the fluid system lines originating from the lower end of probe 14 (now in its raised position) and discharging into waste trap accumulator 47. Thus, the system lines are cleared or purged of any residue which may have otherwise have remained therein. This period of purging is designated 75 on the trace 62.

Subsequently, at time M in FIG. 2, both solenoids 42 and 54 are deenergized to permit their related valves 43, 56 to close so as to place the system in a ready condition for the next examination of the next subsequent sample.

From the foregoing, it will be readily evident that by introducing a bubble of vacuum into the system employing a flow-through chamber after the extraction probe 14 has been submerged beneath the surface of liquid sample to be examined, the system is assured that the flow-through chamber will fill to a proper level even where only a small amount of sample is available for examination. Heretofore, in other system as where the probe is subjected to a continuous application of vacuum as it enters the sample in the test tube, it has been observed that even with a considerable volume of sample available, it is possible for the entire sample to be drawn completely through the examination cell and leave too small a volume of sample remaining in the analysis chamber to provide a proper reading or analysis.

By keeping the lines between valve 43 and chamber 12 relatively short and clear, most of the effect of the bubble of vacuum" will be applied directly to the volume within the flow-through chamber 12 (and hence probe 14) rather than to the connecting lines and thereby enhance the eicient operation of the system.

Further, it is to be observed that sample is not returned to the test tube for discharging as waste so as to contribute to contamination problems at that point. Accordingly, it will be readily evident that the large volume of air purging the lines subsequent to each analysis serves to eliminate contamination as might otherwise occur.

Finally, means have been provided for stirring liquid sample carried in the test tube ll immediately prior to its extraction by probe 14 so that it will be in a thoroughly mixed state and ready to be examined while remaining free of contamination resulting from stirring successive samples with the same device.

Accordingly, immediately upstream of probe 14, a stirring assembly 7l has been provided comprising an actuator plunger 72 movable between retracted and advanced positions within a cylinder 73 coupled to air line 19 so as to receive air pressure simultaneously with the application of air pressure to plunger 18. Plunger 72 carries a crosshead 74 which supports an elongated hollow stainless steel tube or probe 76.

The upper end of tube 76 is directly connected by line 77 to a small capacity air pump 78 of the type used in small aquariums for injecting air bubbles into the water. A valve restriction 79 serves to control the volume of air being passed along line 77 to be discharged via the lower end of probe 76. lri this manner, as actuator 72 carries probe 76 into sample located in test tubes ll, the outwardly discharging bubbles of air from pump 78 will serve to stir the liquid sample in a gentle manner.

Means are provided serving to clean the exterior of probe 76 whereby each successive sample will be stirred by a clean probe and thereby avoid contamination by residue clinging to the probe.

Probe 76 is disposed within a cylindrically shaped absorbent material 81 such as absorbent cloth disposed in wiping relation with respect to the exterior of probe 76 so that, upon withdrawing probe 76, any sample clinging to the outside of the probe will be absorbed in the absorbent material 8l. Thus, as probe 76 enters the next following test tube 11 for stirring; it will not carry a residue of the preceding sample and contamination will be avoided.

Thus, as shown best in FIG. 4, a plastic cylindrical holder 85 is formed with a bottom opening 87 to accommodate passage of tube 76 into and out of holder 85. Holder 85 is supported from the stationary crosshead 80 in a readily releasable manner whereby the absorbent material 81 can be removed and replaced by a fresh supply from time to time. Crosshead 80 is mounted to the upper end of actuator cylinder 73 to carry holder 85 in stationary depending relation` Accordingly, the upper end of holder 85 is formed with an enlarged rib or conventional bulb edge (not shown) in order to snap into an annular recess (not shown) formed within the removable cap 88. Cap 88, of course, is provided with an opening 89 to accommodate movement of probe 76. The underside of crosshead 74 carries a resilient retaining latch 91 formed with a catch portion 91a disposed to engage the flat under edge of cap 88 for supporting holder 85. Stationary retaining elements 92 are also carried from the underside of crosshead 74 for similarly engaging the under edge of cap 88 whereby the cap 88 is engaged at three spaced points.

Accordingly, a length of absorbent material, such as cloth, is rolled about probe 76 and then both are inserted into holder 85. Cap 88, previously positioned onto probe 76, is then snapped in place on the end of holder 85. The holder assembly may then be positioned onto the lower side of crosshead 80. By sliding holder 85 along probe 76, ultimately cap 88 engages the catch 91a so as to be supported in place.

In order to provide an appropriate timed relationship between the point where stirring occurs and the point in time when sample is to be extracted, there is shown in FIG. 3 a mounting support 82 carrying a thumbscrew 83 arranged to cooperate with any one of a number of threaded holes 84 extending along the length of a mounting strip 86.

In operation; it will be readily evident that a method of automatically handling fluid sample transported in open containers moving along a predetermined path has been provided comprising the steps of submerging the end of a suction probe beneath the surface of sample in one of the containers, connecting the other end of the probe to form a path in fluid communication to an analysis chamber, temporarily introducing a bubble of vacuum into the analysis chamber to withdraw a related portion of sample from the container t0 the chamber for analysis, followed by the further steps of permitting the sample portion to remain in the chamber for a dwell period sufficient to obtain analysis thereof, and then applying suction via the flow path to withdraw the sample portion analyzed and the remaining sample from both the chamber and container respectively, and finally purging the flow path of sample residue by raising the suction probe and drawing large volumes of air therethrough via the analysis chamber for a period sufficient to remove the residue of sample from the flow path and the analysis chamber.

In addition to the above, additional preliminary stirring steps are pursued whereby the sample may be stirred without contaminating one sample with the residue of another carried on the stirring element.

Accordingly, prior to submerging the end of the suction probe as indicated above, the preliminary steps may be taken comprising the simultaneous insertion of a hollow probe into sample disposed in a container upstream of the location of the suction probe, followed by the steps of blowing air through the hollow probe into sample for the period of submergence of the suction probe. Thereafter, the hollow stirring probe is withdrawn while simultaneously wiping the exterior thereof with an absorbent material serving to remove residue of the stirred sample.

I claim:

l. In a system for automatically successively withdrawing liquid sample for examination from each of a series of advancing containers the combination comprising a hollow probe to be submerged in sample in each container, means movable between retracted and advanced positions holding said probe disposed for entry into each said container, an analysis chamber for receiving sample drawn from said containers for examination chamber a fluid flow channel extending between said chamber and said probe, a low-pressure vessel, means for maintaining a partial vacuum substantially continuously in said vessel, means forming a flow path between said vessel and said chamber, and valve means operable upon submerging said probe into sample in the containers for momentarily subjecting the analysis chamber, probe and sample to said partial vacuum from said vessel for drawing a predetermined portion of said sample into the analysis chamber.

2. In a system for automatically successively withdrawing liquid sample for examination from each of a series of advancing containers the combination comprising a hollow probe to be submerged in sample in each container, means movable between retracted and advanced positions holding said probe disposed for entry into each said container, an analysis chamber for receiving sample drawn from said containers for examination therein, a fluid flow channel extending between said chamber and said probe, a waste accumulation chamber, means serving to form a vacuum in said accumulation chamber, a flow path defined between said chambers for subjecting said analysis chamber to said vacuum of said accumulation chamber, and valve means serving to provide momentary coupling of said accumulation chamber vacuum to said analysis chamber to withdraw sample from the containers via said probe.

3. In a system for handling sample for analysis of a type having a series of sample containers arranged to move in a predetermined path, the combination of a hollow probe movable into and out of sample carried in said containers, an accumulator vessel, means serving to provide a vacuum within said vessel, means forming a fluid flow path from said vessel to said probe, an analysis chamber disposed in said flow path, valve means in said flow path between said chamber and said vessel, means for opening said valve means for a relatively short period of predetermined duration sufficient to transfer by vacuum suction a portion of the sample from said containers when said probe is submerged therein, and means for operating the last-named means when said probe has been submerged in sample in one of said containers.

4. In a system for handling liquid sample according to claim 3 wherein said valve means includes a restriction in said flow path for metering the transfer of vacuum from said vessel to said analysis chamber.

S. ln a system for handling liquid sample for analysis according to claim 3 wherein said flow path includes at least two branches disposed between said chamber and said vessel and said valve means comprises a valve disposed in each of said branches and a fluid restriction in the flow path of one of said branches, and a fluid restriction in the flow path of one of said branches disposed between said vessel and one of said valves, and means serving to open said one valve while closing the other so as to drain fluid in said one branch into said vessel when said probe is disposed in its retracted position.

6. A method of automatically handling fluid sample transported in open containers moving along a predetermined path, comprising the steps of submerging the end of a suction probe beneath the surface of sample in one of said containers, connecting the other end ofthe probe to form a path in fluid communication to an analysis chamber, introducing a bubble of vacuum into said analysis chamber to withdraw a related portion of sample from said container to said chamber for analysis thereof, permitting the portion of sample to remain in said chamber for a period sufficient to obtain analysis thereof, applying suction via said path to withdraw said sample portion and the remaining sample from said chamber and container respectively for discharge thereof, and purging said path of sample residue by drawing air therethrough for a period sufficient to remove said residue of said sample therefrom.

7. A method of handling fluid sample according to claim 6 further including the preliminary steps of submerging the end of a hollow probe into said sample, pumping air through said hollow probe to inject bubbles into said sample to stir said sample, and withdrawing said hollow probe while wiping the exterior thereof with absorbent material to remove residue of sample clinging to said hollow probe.

8. A method according to claim 7 wherein said hollow stirring probe is being submerged in sample carried in one of said containers while said suction probe is being submerged in sample in another of said containers.

9. ln a system for automatically successively withdrawing liquid sample for examination from each of a series of advancing containers the combination comprising a hollow probe movable between retracted and advanced positions to be submerged in sample carried in said containers for withdrawing a portion of same therethrough, a waste accumulator receptacle and means forming a vacuum therein, means including a fluid analysis chamber defining a fluid flow path from said probe to said waste receptacle for transfer of sample thereaiong, valve means in said flow path, and means for momentarily opening said valve means for a predetermined period of relatively short duration when said probe has entered said sample to thereby transfer a predetermined volume of sample to said analysis chamber.

l0. in a system for automatically withdrawing liquid sample for examination according to claim 9, means in said flow path for metering or restricting the effect of coupling said vacuum to said probe to limit the volume of sample withdrawn into said analysis chamber.

ll. ln a system for automatically withdrawing liquid sample for examination according to claim l0 further including another hoilow probe movable between retracted and advanced positions to be submerged in sample carried in said containers for stirring sample therein, means for feeding a stream of fluid through the last-named probe to circulate said fluid in sample when submerged therein for stirring said sample, and absorbent means disposed in wiping relation to said stirring probe to remove residue of sample therefrom upon withdrawal of the stirring probe from said sample.

l2. ln a system for automatically withdrawing liquid sample for examination from each of a series of advancing containers, a hollow probe movable between retracted and advanced positions to be submerged in sample carried in said containers, means for feeding a stream of fluid through said probe to circulate said fluid in sample when submerged therein for stirring said sample, and absorbent means disposed in wiping relation to said stirring probe to remove residue of sample therefrom upon withdrawal of the stirring probe from said sample.

P04050 UNITED STATES PATENT OFFICE 56 CERTIFICATE oF toREcTioN Patent: No. 3 631 ,726 Dated January 4, 197g Inventor( s) Waite M. Shelton It is certified that error appears in the abete-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 26, change "chamber" to theren- Signed and sealed this 13th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. In a system for automatically successively withdrawing liquid sample for examination from each of a series of advancing containers the combination comprising a hollow probe to be submerged in sample in each container, means movable between retracted and advanced positions holding said probe disposed for entry into each said container, an analysis chamber for receiving sample drawn from said containers for examination therein, a fluid flow channel extending between said chamber and said probe, a low-pressure vessel, means for maintaining a partial vacuum substantially continuously in said vessel, means forming a flow path between said vessel and said chamber, and valve means operable upon submerging said probe into sample in the containers for momentarily subjecting the analysis chamber, probe and sample to said partial vacuum from said vessel for drawing a predeTermined portion of said sample into the analysis chamber.
 2. In a system for automatically successively withdrawing liquid sample for examination from each of a series of advancing containers the combination comprising a hollow probe to be submerged in sample in each container, means movable between retracted and advanced positions holding said probe disposed for entry into each said container, an analysis chamber for receiving sample drawn from said containers for examination therein, a fluid flow channel extending between said chamber and said probe, a waste accumulation chamber, means serving to form a vacuum in said accumulation chamber, a flow path defined between said chambers for subjecting said analysis chamber to said vacuum of said accumulation chamber, and valve means serving to provide momentary coupling of said accumulation chamber vacuum to said analysis chamber to withdraw sample from the containers via said probe.
 3. In a system for handling sample for analysis of a type having a series of sample containers arranged to move in a predetermined path, the combination of a hollow probe movable into and out of sample carried in said containers, an accumulator vessel, means serving to provide a vacuum within said vessel, means forming a fluid flow path from said vessel to said probe, an analysis chamber disposed in said flow path, valve means in said flow path between said chamber and said vessel, means for opening said valve means for a relatively short period of predetermined duration sufficient to transfer by vacuum suction a portion of the sample from said containers when said probe is submerged therein, and means for operating the last-named means when said probe has been submerged in sample in one of said containers.
 4. In a system for handling liquid sample according to claim 3 wherein said valve means includes a restriction in said flow path for metering the transfer of vacuum from said vessel to said analysis chamber.
 5. In a system for handling liquid sample for analysis according to claim 3 wherein said flow path includes at least two branches disposed between said chamber and said vessel and said valve means comprises a valve disposed in each of said branches, and a fluid restriction in the flow path of one of said branches disposed between said vessel and one of said valves, and means serving to open said one valve while closing the other so as to drain fluid in said one branch into said vessel when said probe is disposed in its retracted position.
 6. A method of automatically handling fluid sample transported in open containers moving along a predetermined path, comprising the steps of submerging the end of a suction probe beneath the surface of sample in one of said containers, connecting the other end of the probe to form a path in fluid communication to an analysis chamber, introducing a bubble of vacuum into said analysis chamber to withdraw a related portion of sample from said container to said chamber for analysis thereof, permitting the portion of sample to remain in said chamber for a period sufficient to obtain analysis thereof, applying suction via said path to withdraw said sample portion and the remaining sample from said chamber and container respectively for discharge thereof, and purging said path of sample residue by drawing air therethrough for a period sufficient to remove said residue of said sample therefrom.
 7. A method of handling fluid sample according to claim 6 further including the preliminary steps of submerging the end of a hollow probe into said sample, pumping air through said hollow probe to inject bubbles into said sample to stir said sample, and withdrawing said hollow probe while wiping the exterior thereof with absorbent material to remove residue of sample clinging to said hollow probe.
 8. A method according to claim 7 wherein said hollow stirring probe is being submerged in sample carried in one of said containers while said suction probe is being submerged in sample in another of said containers. Pg,19
 9. In a system for automatically successively withdrawing liquid sample for examination from each of a series of advancing containers the combination comprising a hollow probe movable between retracted and advanced positions to be submerged in sample carried in said containers for withdrawing a portion of same therethrough, a waste accumulator receptacle and means forming a vacuum therein, means including a fluid analysis chamber defining a fluid flow path from said probe to said waste receptacle for transfer of sample therealong, valve means in said flow path, and means for momentarily opening said valve means for a predetermined period of relatively short duration when said probe has entered said sample to thereby transfer a predetermined volume of sample to said analysis chamber.
 10. In a system for automatically withdrawing liquid sample for examination according to claim 9, means in said flow path for metering or restricting the effect of coupling said vacuum to said probe to limit the volume of sample withdrawn into said analysis chamber.
 11. In a system for automatically withdrawing liquid sample for examination according to claim 10 further including another hollow probe movable between retracted and advanced positions to be submerged in sample carried in said containers for stirring sample therein, means for feeding a stream of fluid through the last-named probe to circulate said fluid in sample when submerged therein for stirring said sample, and absorbent means disposed in wiping relation to said stirring probe to remove residue of sample therefrom upon withdrawal of the stirring probe from said sample.
 12. In a system for automatically withdrawing liquid sample for examination from each of a series of advancing containers, a hollow probe movable between retracted and advanced positions to be submerged in sample carried in said containers, means for feeding a stream of fluid through said probe to circulate said fluid in sample when submerged therein for stirring said sample, and absorbent means disposed in wiping relation to said stirring probe to remove residue of sample therefrom upon withdrawal of the stirring probe from said sample. 